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Type of flour and starter activity- A SCIENCE EXPERIMENT

lepainlavie's picture

Type of flour and starter activity- A SCIENCE EXPERIMENT

Hello, I'm new to this site but I really needed some suggestions from experienced bakers for a science project that I'm planning to do it school.

I want to measure the different rates of activity of starters made with different types of flours (whole wheat, refined wheat, rye, corn meal(?), corn flour(?), rice(?) etc), keeping all the other variables constant, of course.

If I'm not wrong, starter activity depends on the amount of starch (what the microorganisms feed on) and possibly the amount of gluten in the flour (traps in the CO2 bubbles as it is formed), correct? Then hypothetically, since the rice and corn flour have the highest starch content, they should allow for the starter to form very quickly? But also as they don't have much gluten (if at all), the starters won't visibly rise a lot?


Before I actually started the experiments I just wanted to question whether:

1.) This would actually work- if I prepare multiple small batches of starters and make each of the starters with one type of flour beginning to end, will the non-conventional flours actually make an active starter?

2.) Will the different starters yield a big enough difference in their activity that I'll be able to write an analysis on it?

3.) Are there any other factors that affect starter activity other than starch and gluten content?

phaz's picture
  1. It'll work, but like any valid experiment, the key is in the method.
  2. I would imagine that's the purpose of the experiment, so you'll see
  3. 2 will tell ya


lepainlavie's picture

Thank you!

I just wanted to ensure that I wasn't starting an experiment that would lead to a dead end.

pmccool's picture

you'll probably be able to grow starters from almost any flour.  I think you will find that the presence or absence of gluten is a non-issue.  But, hey, that's what your experiment is all about.  Have fun with it!


lepainlavie's picture

Thanks for your reply Paul, I look forward to finding out the results of my experiment!

happycat's picture

You need to do some background reading on starters, their composition, what changes and what interacts.

You really need to define your terms operationally. "Activity" has no operational definition (not observable, measurable, or meaningful). If you just mean fluffing up, that's not the same as having a healthy yeast colony. It's usually a lot of competing bacteria at the beginning. That means bacteria in different flours, and/or on your hands and utensils may cause fluctuations not necessarily related to starch. Some flours include enzymes that help with breaking down starches into sugars. That's another complication. Over time, the composition of starters changes based on the activity of the yeast and lactobacillus. See the first point above.

For proper control to isolate starch, you would need to remove confounding influences. 

lepainlavie's picture

Thanks for the reply!

Yes, I do understand that the term "activity" is vague and that the dependent variable should be quantifiable. I was thinking of measuring the amount of fluffing up, but you mentioned it even before I could. I didn't know that fluffing up didn't always mean a healthy yeast colony, so thanks for that input!

My independent variable isn't necessarily the amount of starch in the flours, but rather the flours themselves, including everything that it constitutes of, be it the enzymes, gluten levels etc, and I just mentioned the starch levels as I needed to list possible factors that would influence how I developed my hypothesis.

Your reply gave me a lot to think about, and I realize that I have some things to sort before starting with the experiment. Since this is just an experiment for a high school project, I won't be expected to remove confounding influences out of my control, but mentioning what you stated above as limitations for the experiment will definitely add value to my analysis. Thank you!